Lumbar Provocation Discography/Disc Access: Standard Fluoroscopic Techniques

Abstract

This chapter describes and demonstrates strategies to utilize anteroposterior (AP) and lateral imaging to optimally drive the needle tip to a lumbar disc’s central target. It also includes additional information about discographic image interpretation.

keywords

Discogram, Discography, Fluoroscopy, Lumbar, Lumbar disc, Lumbosacral, Manometer, Provocation

Note: Please see pages ii , iii for a list of anatomic terms/abbreviations used throughout this book.

This chapter describes and demonstrates strategies to utilize anteroposterior (AP) and lateral imaging to optimally drive the needle tip to a lumbar disc’s central target. It also includes additional information about discographic image interpretation.

Trajectory View

Confirm the level (with the AP view).
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  Tilt the fluoroscope’s image intensifier cephalad or caudad.
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  Line up the superior end plate (SEP) of the caudad vertebral body for the individual level being targeted.
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  Optional: Place an abdominal pillow lateralized ipsilateral to the needle entry side to reduce lumbar lordosis and to obtain 5 to 10 degrees of additional obliquity.
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  Lay patients with protuberant abdomens slightly oblique, so the needle entry side is elevated; their abdomen may otherwise theoretically push the retroperitoneum into the needle’s trajectory.
Oblique the fluoroscope’s image intensifier ipsilateral to the needle entry ( Fig. 17A.1 ).
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  Position the fluoroscope such that the superior articular process (SAP) is bisecting or nearly bisecting the SEP.
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  The target needle destination is the part of the disc immediately anterior to the junction of the inferior aspect of the SAP and SEP.
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  Adjust the degree of angulation for each individual intervertebral disc level.
Fig. 17A.1

A , Fluoroscopic image of a trajectory view with the needle in position. B, Radiopaque structures. The SAP bisects the SEP. C, Radiolucent structures.
Place the needle parallel to the fluoroscopic beam.

Notes on Positioning in the Trajectory View

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For each level, the setup is individualized by changing the oblique angulation and tilting of the image intensifier.
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For time efficiency and to minimize radiation, do not transition between the AP and lateral views or vice versa until all intended needle levels have been placed (trajectory view). Then, rotate to the alternate view. If needed, perform minor adjustments to all needles before re-checking.

Trajectory View Safety Considerations

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Avoid the exiting spinal nerve. Superior or lateral migration of the needle tip can contact the spinal nerve.
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Maintain the needle tip immediately anterolateral to the inferior base of the SAP and rostral to the SEP, i.e., “low in the hole” at the SAP/SEP junction.
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Avoid the dura. While advancing the needle toward the disc, do not drive too far medial until entering the disc. A medial straying needle can enter the dura and thecal sac (TS).

Optimal Needle Position in Multiplanar Imaging

Optimal Needle Positioning in the Anteroposterior View ( Fig. 17A.2 )

The “true” AP visualization of each individual intervertebral disc is imperative (see Chapter 3 for discussion on “true” AP). The geometric center of the disc is in line with the position of the spinous process of the superior vertebral body.

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Avoid advancement beyond the geometric center of the intervertebral disc (i.e., the nucleus pulposus) in this (AP) view.
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Use the lateral “safety view” for needle advancement.
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There are no consistent safety considerations in this view.

Optimal Needle Positioning in the Lateral View ( Fig. 17A.3 )

Position the C-arm to obtain a “true” lateral view of each intervertebral disc for the advancement of the needle. This view is the safety view.

Notes on Optimal Needle Position

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The target needle position is within the geometric center of the intervertebral disc (i.e., the nucleus pulposus).
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The C-arm may need to be transitioned from the lateral and AP views multiple times to safely and successfully navigate the needle.
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See Table 17A.1 : Using the Anteroposterior and Lateral Fluoroscopic Views to Triangulate/Calculate Axial Needle Tip Position, With Associated Corrections and Clinical Pearls

Safety Considerations

Avoid the ventrally located aorta and the inferior vena cava.
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  Do not advance too far ventrally.
Avoid the spinal canal.
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  Confirm that the needle tip is intradiscal before advancing the needle tip medially to avoid TS puncture dorsal to the disc.